principal

• principall (obsolete)

From Middle English principal, from Old French principal, from Latin prīncipālis.

• IPA^(key): /ˈpɹɪnsɪpəl/, /ˈpɹɪnsəpəl/

• Audio (US)

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• Audio (AU)

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• Hyphenation: prin‧ci‧pal
• Homophone: principle

principal (comparative more principal, superlative most principal)

1. Primary; most important; first level in importance.

   Smith is the principal architect of this design.

   The principal cause of the failure was poor planning.

   • 1725, Homer, “Book IX”, in [William Broome], transl., The Odyssey of Homer. […], volume II, London: […] Bernard Lintot, →OCLC, page 186:

     In a word, the Epiſodes of Homer are complete Epiſodes; they are proper to the ſubject, because they are drawn from the ground of the fable; they are ſo joined to the principal action, that one is the neceſſary conſequence of the other, either truly or probably: and laſtly, they are imperfect members which do not make a complete and finiſhed body; for an Epiſode that makes a complete action, cannot be part of a principal action; as is eſſential to all Epiſodes.

   • 1995, Madeleine Cabos, Baedeker Paris, page 105:

     The principal treasure of ths department, however, is the Stele of Hammurabi (1792—1750 B.C.), king of the first Babylonian kingdom, a basalt cylinder 2.25m/7ft 5in. inscribed with Hammurabi's laws written in Akkadian in cuneiform script.

   • 2005, Ruth N. Collins, “Application of Phylogenetic Algorithms to Assess Rab Functional Relationships”, in Sidney P. Colowick, Alan Hall, editors, Methods in Enzymology, volume 403, page 22:

     In theory, there are the same number of principal components as there are variables, but in practice, usually only a few of the principal components need to be identified to account for most of the data variance.

   • 2022, Tanya Reilly, The Staff Engineer's Path‎, O'Reilly, →ISBN:

     I understand that feeling. Through 20 years in the industry, I've stayed on the staff engineer's path, and I'm now a senior principal engineer, parallel to a senior director on my company's career ladder.

2. (obsolete, Latinism) Of or relating to a prince; princely.
   • 1590, Edmund Spenser, “(please specify the book)”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie, →OCLC:

     But walkt at will, and wandred to and fro, / In the pride of his freedome principall.

3. (mathematics) Chosen or assumed among a branch of possible values of a multi-valued function so that the function is single-valued.

   Two is the principal square root of 4. Both −2 and +2 are square roots of 4.

Principal should not be confused with principle. Principle is always a noun, which is sometimes erroneously used with the meaning of the adjective principal.

• Incorrect: He is the principle musician in the band
• Correct: He is the principal musician in the band

Similarly principal (or principally) may sometimes erroneously get used as an adjective form of principle. Possible alternatives for an adjective with a meaning closer to the noun principle are fundamental and ethical.

• Incorrect: I have principal objections.
• Correct: I have ethical objections.

This can vary in other languages, for example in Dutch where the noun principe does have an adjective form in principieel. This can be a source of confusion if a Dutch speaker assumes an adjective form of principle would also exist in English which may lead them to erroneously use the similar-sounding adjective principal in an English text for this purpose. Principal is generally not used in the comparative or superlative in formal writing, as the meaning is already superlative. However, like unique, it is sometimes used in this way.

• (primary): chief, main, primary

• principally

principal (countable and uncountable, plural principals)

1. (finance, uncountable) The money originally invested or loaned, on which basis interest and returns are calculated.

   A portion of your mortgage payment goes to reduce the principal, and the rest covers interest.

   • 1902, William Pember Reeves, State Experiments in Australia and New Zealand, volume 1, Cambridge University Press, published 2011, page 342:

     In March 1902, I find in the statement of liabilities and assets £711 put down as arrears of interest, but there is no entry of arrears of principal.

   • 2012, Denis Clifford, Plan Your Estate, 11th Edition, NOLO, US, page 298,

     For instance, in some states, dividends that have automatically been reinvested will be treated as principal.

   • 2012, Fred Steingold, Legal Forms for Starting & Running a Small Business, page 88:

     If you know the principal amount, the interest rate, and the number of years the payments will be made, you can consult an amortization calculator or schedule to arrive at the monthly payment.

2. (Canada, US, Australia, New Zealand) The chief administrator of a school.
   • 1971, Louis Kaplan, Education and Mental Health, page 413:

     The important administrative figure to the teacher is the school principal.

   • 2008, Brian Dive, The Accountable Leader: Developing Effective Leadership Through Managerial Accountability, page 212:

     The problem was neatly summed up by one principal in Australia who said recently: ‘There is no incentive for me to develop my best teachers to become my successor. […] ’

   • 2009, Colin J. Marsh, Key Concepts for Understanding Curriculum, page 132:

     Now renamed Teaching Australia, its officers are undertaking exploratory steps in developing professional standards for school leaders. A National Standards Drafting Group of volunteer principals is currently drafting principal standards (Teaching Australia, 2007).

   • 2011, U.S. Department of Labor, Occupational Outlook Handbook 2011-2012, page 45,

     Principals are now being held more accountable for the performance of students and teachers, while at the same time they are required to adhere to a growing number of government regulations.

3. (UK, Canada) The chief executive and chief academic officer of a university or college.
   • 1967, University of Edinburgh Graduates′ Association, University of Edinburgh Journal, Volumes 23-24, page 314,

     Unlike the students, Principal Robertson, who now resided almost alone in the College, continued to use the accustomed route on his visits to the Old Town; and it “became the joke of the day that from being the principal gate it had become only a gate for the Principal.”⁵

4. (law) A legal person that authorizes another (the agent) to act on their behalf; or on whose behalf an agent or gestor in a negotiorum gestio acts.

   When an attorney represents a client, the client is the principal who permits the attorney, the client′s agent, to act on the client′s behalf.

   My principal sells metal shims.

   • 1958, American Law Institute., Restatement of the Law, Second: Agency 2d, volume 7, page 533:

     The firm admitted the amount owed, but averred as an affirmative defense that it had hired the expert as an agent of a disclosed principal, the client.

   • 1966, Pan American Union, The Marketing Structure for Selected Processed Food Products: In Sweden, Denmark, Norway, The Federal Republic of Germany, Canada and the United Kingdom, page 34:

     A food broker has been defined as an independent sales agent who performs the services of negotiating the sale of food and/or grocery products for and on account of the seller as principal.

   • 2009, California Continuing Education of the Bar, California Probate Code, page 375,

     An attorney-in-fact has a duty to act solely in yhe interest of the principal and to avoid conflicts of interest.

5. (law) The primary participant in a crime.

   Coordinate term: accessory

   Hypernym: accomplice

   • 1915, Eugene Allen Gilmore, Wiliam Charles Wermuth, Modern American Law, page 125:

     The accessories may be prosecuted, tried and punished, though the principal has not been prosecuted or has been acquitted.

6. Either party in a duel.
   • 1868, Andrew Steinmetz, The Romance of Duelling in All Times and Countries, volume I, London: Chapman and Hall, page 107:

     The old man raised his arm as though it had been palsied, and fired, of course without effect. The other principal immediately deloped, much to the satisfaction of my friend and all present.

7. (Canada, US) A partner or owner of a business.
8. (music) A diapason, a type of organ stop on a pipe organ.
9. (architecture, engineering) The construction that gives shape and strength to a roof, generally a truss of timber or iron; or, loosely, the most important member of a piece of framing.
10. The first two long feathers of a hawk's wing.
    • 1579, Immeritô [pseudonym; Edmund Spenser], The Shepheardes Calender: […], London: […] Hugh Singleton, […], →OCLC; reprinted as H[einrich] Oskar Sommer, editor, The Shepheardes Calender […], London: John C. Nimmo, […], 1890, →OCLC:

      a birde whose principals be scarce growne out

    • 1856, John Henry Walsh, Manual of British Rural Sports:

      The first two feathers - Principals

11. One of the turrets or pinnacles of waxwork and tapers with which the posts and centre of a funeral hearse were formerly crowned[1]
12. (obsolete) An essential point or rule; a principle.
    • 1847, Great Britain. Committee on Education, Minutes of the Committee of Council on Education, page 446:

      Set two classes of monitors to question each other; so that one may try to outquestion the other. Explain to them the principal of every subject they have to teach.

13. A dancer at the highest rank within a professional dance company, particularly a ballet company.
14. (computing) A security principal.
15. A main character or lead actor.
    • 1973 August 4, J. Ralf Green, “The Hossenpfepper Column”, in Gay Community News, page 3:

      Silverberg also gives the reader reader some excellent character insight; deep probes into the minds of all the principals bring the reader closer to the persons involved than might be thought possible with the plot so far removed from the realm of normality.

Principal should not be confused with principle. They are both nouns, but principle means "moral rule", while principal may refer to a person or entity.

• Incorrect: He is the principle of our school
• Correct: He is the principal of our school

• (original money invested or loaned):
• (school administrator): headteacher n, headmaster m, headmistress f
• (chief executive and chief academic officer of a university or college): dean
• (one under whose direction and on whose behalf an agent acts): client
• (company represented by a salesperson):
• (primary participant in a crime): ringleader
• (owner of or partner in a business): proprietor
• (organ stop): diapason

• (original money invested or loaned): interest
• (school administrator): master, mistress, headteacher
• (chief executive and chief academic officer of a university or college): bursar
• (primary participant in a crime): accessory

• principalship

• PITI payment
• prince
• principality
• principle

Borrowed from Latin prīncipālis.

• IPA^(key): (Central, Balearic, Valencian) [pɾin.siˈpal]

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principal m or f (masculine and feminine plural principals)

1. main; principal
   • a partir de l'any 1799 Urgias va ser un dels principals animadors del Parnàs Alguerès

• principalment

• principalitat
• principi

• “principal” in Diccionari de la llengua catalana, segona edició, Institut d’Estudis Catalans.

Borrowed from Latin prīncipālis.

• IPA^(key): /pʁɛ̃.si.pal/

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principal (feminine principale, masculine plural principaux, feminine plural principales)

1. main, key, principal

   l’un des principaux problèmes ― one of the key problems

   les principales ethnies du pays ― the principal ethnic groups of the country

This is one of the French adjectives that can occur either before or after the noun. When located before the noun, the adjective is more strongly emphasized.

• conseiller principal d’éducation
• plat principal
• principalement
• séquence principale

principal m (plural principaux, feminine principale)

1. someone or something which is important, key, paramount

   les principaux du royaume ― the chief men of the kingdom

2. principal (school administrator)
3. (finance) principal (the money originally invested or loaned)

• “principal”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.

• Rhymes: -al
• Hyphenation: prin‧ci‧pal

principal m or f (plural principais)

1. main, principal

• principalmente

• Audio (Languedocien)

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principal m (feminine singular principala, masculine plural principals, feminine plural principalas)

1. main, principal

From Latin principālis (“first; principal”), from prīncipium (“beginning”).

• Rhymes: -al, -aw
• Hyphenation: prin‧ci‧pal

principal m or f (plural principais)

1. main; principal (most important)

   Synonym: primário

2. fundamental; essential

   Synonyms: see Thesaurus:importante, Thesaurus:importante

3. (astronomy, of a heavenly body) having another body orbiting it

   Synonym: primário

4. (grammar, of a sentence) not subordinate

For quotations using this term, see Citations:principal.

• (antonym(s) of “main”): secundário
• (antonym(s) of “fundamental”): See Thesaurus:importante
• (antonym(s) of “having another body orbiting it”): orbitante
• (antonym(s) of “said of a sentence which is not subordinate”): subordinado

• principalmente

principal m (plural principais)

1. prelate of a religious, educational or commercial institution

   Synonyms: diretor, prelado

For quotations using this term, see Citations:principal.

• principalidade
• príncipe
• princípio

Borrowed from French principal, from Latin principalis.

• IPA^(key): /prin.t͡ʃiˈpal/

principal m or n (feminine singular principală, masculine plural principali, feminine and neuter plural principale)

1. principal, primary, chief, foremost

   Synonym: central

   Antonym: secundar

Inherited from Old Spanish prinçipal, principal, borrowed from Latin principālis.

• IPA^(key): (Spain) /pɾinθiˈpal/ [pɾĩn̟.θiˈpal]
• IPA^(key): (Latin America) /pɾinsiˈpal/ [pɾĩn.siˈpal]

• Audio (Colombia):

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• Rhymes: -al
• Syllabification: prin‧ci‧pal

principal m or f (masculine and feminine plural principales)

1. main, most important
2. essential

principal m (plural principales)

1. chief, boss

• “principal”, in Diccionario de la lengua española, Vigésima tercera edición, Real Academia Española, 2014

principal c

1. a principal; one who directs another (the agent) to act on one's behalf

• princip
• principiell